Electrical load breaking device



Dec. 14, `1948. P. B. HoYE ELECTRICAL LOAD BREAKING DEVICE 6 Sheets-Sheet l Filed Dec. 20,1943

IN V EN TOR.

P. B. HQYE ELECTRICAL LOAD BREAKING DEVICE Dec. 14, 1948.

www www www Filed Dec. 20, 1943 Dec. 14, 1948. P. B. HoYE ELECTRICAL LOAD BREAKING DEVICE e'snqets-sneet s Fild nec. 2o. 194s N VEN TOR.

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ELECTRICAL LOAD BREAKING DEVICE 6 Shouts-Sheet 5 Filed Dec. 2x0, 1943 INVENTOR. l

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Patented Dec. 14, 1948 A kUNITED sTATss PATE Y'aisselles NT OFFICE ELECTRIC@ LOADABREAKING DEVICE reeel-n. Haye, Manteaux., assignmto Electrical Engineers Equipment Co., Melrose Park, Ill., a. corporation of Iliinois a `1 The present invention loadbreakng device of the air break type.`

One of the features ofthe invention resides relates to an electrical` in an improvedconstruction and arrangement of 1 arcing contacts and arc extinguishing chamber in which the arc extinguishing action is performed primarilyby causing the gaseous products of the arc to be projected at a relativelyl high pressure "and a relatively high velocity directly into the arc itself, More particularly, this arc extinguishing chamber comprises an improved arrangement of aligned tapered throats which-` direct the gaseous products ofthe arc diagonally inwardly into thejpath of the arc at an oblique angle counter to the direction oftravel of the` movablearcing contact. The `high velocity, high pressuredischarge of thev gaseous product of the produce a greatly accelerated separating motionv between the two arcing contacts.

Another feature ofthe invention resides in a load breaking switch of the above general` type in whichthe arc `extinguishing contacts and arc :c

extinguishing chamber operate in conjunction with main load carrying contacts, and wherein these main load carrying contacts and the arc extinguishing ,contacts are arrangedconcentri# cally in a compact tubular nesting or assembly.

n Another Afeature of the invention resides in a load vbreaking switch of the above generaltype in which th'e arc extinguishing contacts and the arc extinguishing chamber can be 'readily removed asa complete interrupter unit for inspection, repair or substitution through the use of a switch stick actuated from a remote point, and

- without the necessity' of opening the main contacts or disconnecting these main contacts from the line. .This enables the interrupter unit to be readily examined for possible repair or replacement without opening th'e line through the main contacts. n

Other objects, features, and advantages ofthe Application December `20, 1943, Serial No. 514,944

' `lllllaixns. (Cl. 200-146) n a i 2 Y Figure 1 is a fragmentary front elevational view showing a load breaking isolator switch embodying the invention;

' Figure 2 is a fragmentary side elevational view thereof;

Figure 3 isa fragmentary vertical axial sec-- tional view through one of the arc extinguishing chambers, showing the cooperation of the tw arcing contacts therein; n

Figure 4 is a fragmentary sectional view showing the lining rings of the arc extinguishing chamber on a larger scale; a

Figure 5 is a fragmentary view similar to Figure `3, showing the relation of thearcing contacts at different stages of the switch opening opera-- tion;

Figure 6 is a similar fragmentary view showing the positions of the main contacts and arcing contacts -in a still further stage of the switch opening operation; f

n Figure 7 is a fragmentary vertical axial section similar to Figure Sashowing a modified construction in which the controlled or relatively movable arcing contact is gas impelled, this view showing the switch closed;

Figure 8 is a similar fragmentary view taken `lower `clown on the switch assembly, this view showing the switch in the act of opening;

i Figure 9 is a fragmentary section, similarto Figures 3 and 7, showinganother modiedconstruction;

Figure 10 is a View similar'toli'igure 9, showing the latter embodiment of switch in open circuit position; n

invention will appear from the following de-` tailed description of certain Vpreferred embodi ments of the invention. a a a In the accompanying drawings illustrating such embodiments: n

, Figure 11 is a detail elevational view showing the arrangement for detachably locking the removable interrupter unit in the switch assembly; and

Figure 12 is `a fragmentarydetail view showing how the removing tool engages overthe upper end of the interrupter unit preparatoryto removing the latter. c t

In the embodiment of my invention illustrated in Figures 1 to 6, inclusive, I havefshown the in-` vention incorporated in an isolatorsvlitcli, but it win be understood that the invention is not 11nited thereto. Referring to Figures 1 and` 2, this isolator switch is shown as being of the three phase type, having the three disconnecting switch units A, B, and `C enclosed within a main housprises anupper insulating shell il eirtendlng` up into an upper terminal housing 55 for' making any suitable connection with transformer terminals or any other circuit connections. Disposed at one side of the main housing or frame is an operating handle 56 which is mounted on an `operating shaft 61. Theshaft 51 extendsacross the backoi the main housing or-frame 5i `in` rear of the switch unitsjA, B,xand C. l

` Mounted on the operating shaft 614 just inside each side wall ofthe main housing 5| isa pair a pair of links 6I which extend up for pivotal connectionat 62 withthe ends of `a litter frame 6l; This lifter frame extends across the entire width of the isolator` switch assembly so that it can function as a common actuating element for all three switch units A, B, and C. Pivot ears or lugs 64, extendingjupwardly from theends of this lifter frame,receive the pivot pins 62 at the upper endsoi the links 6l. hIf desired, the vertical `motion of the lifter frame may be guided by guideways on the end or side wallsy ofthe stationary frame 5I.` i

The lifter frame has operative connection with each switch unit A, B. andC through attachmentrings 6 which `are bolted `to the lifter frame at each witch unit. Each attachment ring is cemented or otherwise secured to the outside of a :long insulatingsleeve `B1 which carries and houses `the relatively movable main contact of movement, the reciprocable insulating sleeve I1 of each switching `unit `is carried downwardly,;

thereby causing the movable main contact Il to move down out `of engagement with tionarymain. contact 1L Referring now to the improved arcingfcham-` ber and arcing contacts which I have embodied l in this isolator switch unit, a cup-shaped g mg `si is `extended'down mtu-the upper-,gend or the stationary main contact sleeve 14, thiscup-` oi actuating arms 58 (Figure 2); which are plvotally connected at their upper :ends at Il with@ shaped casting having an outwardly extending ange 82 at itsupper end which seats on the` anchoring ring 15 of the contact sleevle 1l.

Passing down throughapertured corners of the `ilange! are cap screws which tap into threadedholes in the terminal ring 1B. The screws Il also serve to secure a perforated plate or metal` screen 84` across the open top ofthe cup-shapedr t casting 8|. Secured within the cup-shaped'cast-- ing is a spider ring 86 which is formed integral` i with along dash-pot cylinder 81 extending axially ofthe cup-shaped casting `8l. Guided fior,` vertical sliding `movement inlthis cylindermljis the relatively stationary arcing contact 88 `which is in the formof a rod 'extendingdown through the lower `end ofthe guide `cylinder 81.` This relatively stationary arcing contact 88` is `adapted` to have endwise abutmentagainstthe upperend of the relatively movable arcing contact 89,` the its j respective switch unit. lThis movable `main contact is in the form of a long metallic sleeve ll which is rigidly anchored in an inwardly ex- 61, as byan upper ring `6i! pinned or otherwise secured to" sleeve 68 and bearing on the upper end ofthe boss 61', and alower ring 1I threaded,

overthe contact sleeve and bearing against `the lowerzend of theboss. As shown in Figure 2. the

lowerportion of the movable contact sleeve B8 is slotted to iorinilngers 68a, and these converge for sliding contact up `and down along the sides of the stationary terminal post 13 which is rigidly mounted in the lower insulating shell 52. i

j The upper end of the movable main contact 6l is` adapted to have sliding engagement up into the lower end of the tubular mainstationary contact 14. The latterjcontact is in the `form of a sleevehaving a slotted end establishing contact lingers which are converged inwardly for firm `frictional engagement with the outer surface oi' `the movable contact sleeve 68. The .5s

upper end` of the stationary main contact*` 14 is threaded into an anchoring ring 15 which seats .k

ontop of the terminal ring 16, the latter being secured to the top of the upper insulating shell 54, and having an upwardly extending terminal ,t lug'11 for establishing connection with a transformer terminal `or other circuit connection.` A

ring 18, secured around the outside of the ter- 4minal sleeve 1I seats `within the upper portion of the'tubuiar insulator u and'hoidsthe stationaiycontact `14 againstfupward movement. It

will be observed from the foregoing that when the operating handle 56 occupies `the upper position illustrated in the drawings, the movable tending annular boss-61" of the insulating sleeve main contact sleeve 46I occupies the upper position-illustrated in Figure 3, at which time it is completinga circuit down through the Vswitching lunit `by virtue of `its engagement with the slotted lowerportion of the stationary main ccn- Ytact `14. When the operating handle 5B is swung downwardly through substantially degrees of latter also being `in the form of arod which "is` carried `by the movable main `contact '68 'to move indicated generally at 9|.

nally threadedvboss extending downwardly from the cup-shaped casting 8l. Aninternally threaded Vcap 91, composed of fiber or like mate--` rial, screws over the threaded' lower end `of the` inner sleeve 93, this cap serving to hold the outer` sleeve 92 coniined between the boss Stand cap 91, and also serving to `hold the the `arc `ex- 1` tinguishing rings 94 in placewithin `the inner` These lining rings are preferably composed of an insulating material havinghigh` ability to withstandy the destructive actionofan electric arc, while at the same time permitting a certain 4 amount of burning, whereby a substantial amount ofgas is produced. Such a materialistypically represented by horn fibre or the like..` Each ring has a cylindrical outer surface 94u which has a t relatively snug push fit within the` surrounding insulating sleeve 93. Each ring is formed withz a. relatively long tapering throat Mb; the con-I stricted end of which closelysurrounds the arcing electrodes 83 `and 89, only a relatively small annular space intervening `between the fconstricted end `of the throat and the arcingJ`elec` trode. constricted portionof` the throat has `itsiend surface cut backor annularly recessed, as indicated at 94e. This serves the two-foldpurposef` of increasingthe length of the creepage `pathlor area of the arc extinguishingchamber, and also of providing sheltered or protected surfaceslin the staf` That end of each ring formed `with thel the chamber which are not reached directly by the arc. Such will be obvious frornthe fact that the cut-back or recessed area 84o is defined by three walls 84d, 94e, and 84j which increase the total length of` the creepage path considerably at each ring, and which recessed walls are out of the normal path ofthe arc flame and hence are protected against being burned by the direct action of the llame.

The relatively movable I"arcing contact 8s has its lower `end threaded into a circularmetallic mounting-block which isl pinned or screwed to the relatively movable main contact 68. Thus, the relatively movable arcing contact remains i permanently electrically connected with therela- 88 from boss 86. t

The upper or relatively 4stationary arcing contact 88 has a free sliding fit inthe tubular guide 81, and carries a piston |84 which slides in a cylinder |85 in'saidtubular guide. The piston |84 serves both as a stop device and asakoneway retarding device for the upper` arcing contact '88. In the normalclosed position ofthe switch unit (Figure 3) when the main contacts 88 and 14 are in engagement, the lower arcing contact 88 is in abutment `With the upper `arcing contact 88, having forced the upper contact 88 to the raised position illustrated. At this time the piston |04 stands at an intermediate position When the movable main contact 68 and movable arcing contact 88 start down together in a switch opening operation, the upper arcing contact 88 follows the lower arcing contact 89 down. These two arcing contacts are in engagement at the instant that the main contacts start to separate, and hence the two arcing contacts become transposed from a shunt relation to a. series relation. Therefore theymomentarily take over theentire load so that substantially no arc is drawn between the main contacts 68 and 14 in the separation of these main contacts. The arcing contacts remain in engagement until the main contacts have .become well separated whereupon the piston :|84 strikes'the bottom of the cylinder |05 and stops further descent of the upper arcing contact 88. Immediately therewith the arc is drawn as the lower arcing contact continues to move downwardly, and the creation of the arc generates high pressure gases in the `are extinguishing chamber` 8| which immediately drive the upper arcing` contact 88'back in an upward direction so as to accelerate the separation of the arcing contacts.

Referring again to seen that leading from the bottom of the chamber |85 are one or more venting ports |88, and leading from approximately the mid point of the cylinder is another venting passageway |01. The

upper end of the guide member 81 is formed with a counterbore |88 over which screws a cap |88 having venting apertures ||2 therein. A yieldableV abutment disc I I3 seats in the bottom of the counterbore, with a spring ||4 confined between it and the cap|08. An extension rod 88a entends upwardly from the piston |84 and passes freely the cylinder las, 1t will be` through the yieldable abutment (I8 and cap |88. Surrounding this rod, with a rather snug sliding fit, is a valve `ring ||8 which normally `seats on the abutment disc ||8 and closes a valve port l I8 formed centrally in thisdisc. The lower portion of the arcing rod 88 passes through a relatively w snug opening |I1 formed in the bottom i of the cup-shaped casting 8|. When the rapidly expanding gases of the arcforce the contact rod88 upwardly thepiston |84 is free to move unimpeded by any damping action because the ports |88and |81 `admit atmosphere below the piston and because the air confined above the piston `is freely vented out through vvalve port ||8 and past upwardlydisplaced valve disc ||8 and outthrough vents ||2. However, on thereturn motion o! the arcing contact. a very pronounced delaying orimpeding action occurs in in the cylinder |85, as illustratedinFigure 3.

the downwardmotion of the piston |84. During the first part of this downward motion the check valve ||8, seating on the valve port ||8, prevents inilow of atmosphere into the chamber area above the piston; also, `outflow of air from the lower portion of the chamber area is restricted by the ports |88 and |81, and particularlyso after the lower edgeof the piston cuts of! the port |81 so that the venting is coniined to the restricted outflow through' the smaller port |88. By virtue of the above operating relationship, the arcing `contact 88 is made responsive to pressure so'that it is free to move upwardly with a very rapid motion as soonas the arc is drawn, and is impeded against ,return motion so` that an adequate time interval is established' to quench the arc, and also so that there will be so oscillation of the upper arcing contact 88. The restriction through port |88 is not so small, however, that the upper arcing contact might lbe i prevented from following down" directly with the lower arcing contact in the manual switch opening operation. A very supple form of plgtail cr like exible conductor |2| has its lower end anchored under one of the cap screws 88 and has its upper end secured to the upper rod portion 88a by the nuts |22, whereby `the relatively stationary `arcing `contact 88 remains permanently electrically connected to the relatively stationary main contact 14, although being` movable relatively thereto.

Mounted in the lower portion of the cup-shaped casting 8| is a thin cup |24 composed either of perforated sheet metal, wire gaune or the like. Reposing in this perforated cup are-a large number of small balls |28, such as small steel' balls of the type used in `ball bearings. -When the expanding gases of the are drive the upper arc- `ing contact 88 upwardly through the opening ill, they remove all obstruction from this opening so that they can freely discharge upwardly through the perforated cup |24 and balls |28. The top perforated plate or screen 84 prevents the balls from being blown completely out of the assembly. 'I'he balls exert a pronounced cooling and screening action on the discharging gases. `The mode of operation of the `switch should be `apparent from the preceding description, but

These two arcing contacts are in engagement at `the instant the main contacts 88 and 14 start `to separate, and hence the two arcing contacts become transposed froxrr'a` shunt relation to a series relation with respect to the main con- ,accuses l,

tacts. Therefore,- theyl-momentarily take over the entire 'load so` that.;subswntially.4 no` arc is drawn between the"maingcontacts 03 and "14 inthe separation of these'main contacts. vThe arcing contacts Il Il continue to. remain in` engagementnuntil the mainjcontcts `have become lwell separated-(Figure-h whereupon the tact 00.` `'.llhis lower position of the upper arcllngecntactn is mustrateu'in dctteujnnes in Figure 5. Thereuponfthe lower arcing contact starts drawing away the upperl` arcing contact so. that anarc istdrawn between these two contacts. Tlre creation `of o the rarc generates which immediately. onafterthe gas pressure has ,reached a predeterminedfvalue,` `drives the upper arcing contact 03 in an-upwarddirection so as to` `v`acoelerateithe separation of the arcing contacts.

Thlsupper position of-the upper-arcing `contact is illustrated in full linesin Figurev 5. Thereafter,

, hi h, ressuregases inthe arcing chamber 9|, o o o o s n ment the rassembly of` the arc` extinguishing` the downwardreturn motion of the `upper arcingy contact isso delayedpor retarded by the action of the piston-Illinrthe retarding chamber |05 thatthe lower arcin'g contact 00 has ample opporl tunity to reachthe lower end of itsn'iovementv before the upper arcingjcontact candrop down again tc a striking position` Figuren illustrates the switch parts approaching the fullyeopen position, the final degree of separation being some-` what more than is shown in thisl ligure.

Referring again to the arc extinguishing action occurring within thechamber 9|, `the'construction ofthe lining rings, out of horn fiber or other `suitablle insulatingmaterial havinghigh tensile strength gives theselinin'g ringsthe ability to withstand ythe large expansion pressure `from the arc. The` strength of these `lining l rings strengthensthe entire assembly." It should also be noted that the taperingrthroat 94o in` each lining ring controls and di'rects the motion of the expanding gasesso as to create a pronounced turbulentfaction in close proximity to the arc. Also, the very high pressure developed in the rela' tively small arcextinguishing chamber 9| lgreatly assists in interrupting the are., The burning uetion on the liningrings coacts chemically with the fiber composition of these rings so as to nberate a substantial quantity of carbon dioxide, o

, manent attachment to` the lower; malnfcontact ber are constructed and arranged inthe form of a `completely removable interruptor unit, desig-` nated in its entirety, which interruptor unit can be quickly and easily removed and replaced through the simple manipulatlonof a switch hook" o o or` thelike. 'This removal and replacement of the interrupter unitcan be performed while the main switch contacts are "in engagement, or after the "main "switch contacts have been moved to the siiiitchopen position. In this modified` embodichamber Si and associated parts is mountedabove the tubular porcelain insulator 54 instead of with" in this insulator. as was true of the preceding o embodiment.` This upper assembly comprises an outer tube |52 composed of insulating material,

such as Bakelitefor the like, `which is lined with `asisationary metallic tube |53, preferably 'come posed of copper. The` metallic tube |53 has electrical connection` with the stationary main contact 14 through the 'medium'of a threaded` l upper sleeve extension 14a ofsaid maincontact, I this. sleeve extension passing up through the tu?` bular supporting insulator 54 and receiving upper and'lower clamping nuts |54 and |55. The metallio sleeve".|53`has an inwardly extending lower ange |53a which seats onthe terminalring 16 Referring now `to the o removable interrupter w unit designated |50, which is adapted to drop down into the stationary metallic tube |53, this interrupter unit comprises a relativelyheavy` outer metal sleeve IBI within which is mounted whichhas alhigherjdielectric strength than air.

, These chemicaiproducts are created at the point l of highest turbulence or highest rate of now of thegas... Also, as previously remarked, the cui;-` back or recessed area Moat the reducedjthroat end of each lining ring enablesthe lining rings 'Y to telescope or'overlap, andalsoresults in a longer creepage path, Iengthened bythe three walls 94d,`

04e, and 04f,`which longer creepa-ge path ismoreoverprotected against the effect of the arc so that there isa reduced deposition of `metallic particles on this creepage l path owingito the protection `of o the pathirom thefrc. Still further, it should benoted that these lining rings 94 can be easily replaced at relatively small expense, so that there is no necessityof discardingthe entire arc inter` lrupting" assembly. The `arc extinguishing chamber SI1 and upper ageing electrode 80 `can' be re#- moved fromj'the assembly by removing the screws 83 and lifting the cup-shaped casting 8 upwardly out of themain contactsli and '14,this casting l 8| carrying. the upper arcing terminal 38 and arc extinguishing chamber 3|" with it, but leaving lower arcing `electrode l 80 remaining in `peran insulating tube |52, composed of Bakelite` or the like.` The arc extinguishing `chamber 3L` i is formed within thisinsulating tube |02,`the e'X- tinguishing chamber being formed with the` series of liner rings 94 of substantially the same construction described above. The upperend-of o `the Aremovablemetallic tube IBI is counterbored and internally threaded, as indicated at |64, for receiving the threaded lower end oi an upper metallic sleeve |65. Mounted in said` upper sleeve is a swinging latch Iliwhich is pivoted on a cross pin |01 extending transyerselythrough the tube its;` `The upper port-ien of the tubeles is tened i outwardly at `I65a to accommodate .the lateral swinging motion of the forkedupper end"|56a of` the latch |60. Opposite sides of this bell-shaped portion are pinched towards each other to form" o flattened side walls., Formed in these opposite side walls are L-shaped slots |58each comprising the `vertical passageway |08a and the horizontal i passageway |6811.` These slotsareadapted to re` ceive the pin of a switch stick. o The endfof the switch stick preferably has fork `arms `between which extends a transverse pin, or the'stick may i merely `have a laterally projecting pin, possibly formed with, an enlarged `head at the outer end of the pin. In the normal position of the forked Referring now to thejmodifed -constructionlil lustrated in Figures 7 and 8, in such modified ern-` bodiment the upper arcing contact, the lower o arcing contact, andthe arc extinguishing cham-1 upper end |99a` of the latch it is aligned with the vertical passageways |99a so that the transverse pin on the switch hook can be passed down through the vertical portion of the L-shaped slots into engagement with the yoke extremity of the latch, whereupon the switch hook can be moved laterally for swinging the yoke shaped extremity over into registration with the horizontal end of the slots. ProjectingV from one side of the latch or pawl |99 is the latching nose |99b which is adapted to engage in a latching pocket |12 formed in the statonary metallic sleeve |59. The latchv |99 is resiliently held in both its engaged and released positions, thereby locking the interrupting unit to the switch stick until the;

interrupting unit is latched to the stationary socket. and particularly until after the latching nose |99b is engaging in the latching pocket |12. This interlocking function is obtained by the action of two ilat surfaces |13 and |14 formed on the lower edge of the latch and against whichis pressed a spring urged disc or ring |15. This ring is freely slidable within themetallic tube |95 and is urged upwardly by a compression spring |19 confined below the ring. The lower end of the spring |15 bears against a disc-shaped release valve |11 which normally seats on a stationary disc 99a which serves as the upper arclng contact. This contact disc 99a has a raised peripheral flange 99h against which the lower end of the metallic sleeve |95 abuts for anchoring the cont-act disc 88a in place. A central aperture 99a in the disc 99a serves to vent gases from the arc extinguishing chamber 9| when such gases create a pressure adequate to force the release valve disc |11 upwardly, at which time the gases pass upwardly through outwardly disposed ports |11a in the disc |11, and through ports 15a in the detent ring |15. The lower end of the metallic sleeve |9| .is formed with an inwardly extending flange |9|a against which the shoulder |92a of the insulating sleeve |92 is held by the upper arclng contact disc 89a.

The insulating sleeve |92 is formedwith a re` duced extension |921) extending downwardly from the shoulder |92a, and the lower beveled end of this reduced extension abuts against a beveled shoulder |9| formed within the tubular main contact 14. Mounted for vertical sliding movement within this insulating sleeve extension |92b is the lower arclng contact 99a which is normally urged in a downward direction by a compression spring |82. The upper end of this spring bears against a stationary collar |93, which also guides the upper end of the arclng contact, and the lower end of the spring bears `against a movable collar |94 which is pinned to an intermediate part of the contact rod 89a. In the open position of the switch the collar |94 rests against a shoulder |95 formed in the reducedrextension |62b of the insulating sleeve |62. That portion of the contact rod 89a extending downwardly below the collar |94 is sheathed within an insulating tube |89 which has a free sliding fit within the tubular main contact 14 and insulating sleeve extension |92b. A metallic cap 91 screws over a reduced threaded end 99h of the contact rod and serves to hold the insulating tube |89 in place on the rod. It will be observed that when a switch hook is inserted in the slots |99 an-d the latch |99 released, the interrupter unit |59 can be removed in its entirety,such unit comprising the sleeves |9|, |95, insulating tube |92, |9211, upper arclng contact 99a, arc extinguishing chamber 9|, lower arcingcontact 99a, and lower insulating sleeve In the operation of closing the switch the springpressed` arclng contact 99a is pushed upwardly to its circuit closing position, against the pressure of the spring |92, by the action of a spring pressed follow-up' rod |9| which is carried withinthe movable main contact 99. As best shown in Figure 8, it will be seenthat the upper end of the follow-up rod |9| carries acollar |92 which' .serves as a guide for guiding the motion of the upper end of the follow-up rod within the tubular contact 99, and which also` serves as an abut? ment against which bears the upper end of a compression spring |99 surrounding the rod. The

lower end of the follow-up rod is slidably guided The spring |93 is substantially stiffer in deflection strength than the spring |92 which normally urges the lower arclng contact 99a downwardly. Hence it will be seen that in the operation of closing the switch, when the upper end of the `follow-up rod, |9| strikes the lower end of the contact rod 99a `the upper spring |92 yields in deference to the lower spring |93, and,hence the arcing rod 99a is pushed upwardly to closed circuit position in engagement with the upper arclng contact 99a. abuts the upper arclng contact, continued further movement of the movable main contact 99 is absorbed by the lowercompression spring |99. In the completely closedposition of the switch the movable main contact 99 is in resilient engagement over the reduced lower portion of the stationary main contact 14. The upper portion of the movable main contact 99 is slotted to provide a plurality of longitudinal contact fingers, and these are urged inwardly into firm engagement with the stationary main contact 14 by circular garter springs |91 which encircle these contact fingers.

In the operation of opening this embodiment of switch, the movable main contact 99 starts,y

ing contact 99a.4 Hence, the arclng contacts,

' which were previously. in shunting relationto the main contacts 98 and 14, are n ow transposed to series relation with respect to theselmain contacts for. momentarily Acarrying the entire load.

This avoids any arclng at the'instant of separa-- velops high gaseous pressures in the arc extin` guishing chamber 9|, which pressures act` l After the lower arclng contact,

v 11 l upwardly against the release valve |11 and also act downwardly against the lower arcing contact lla. This Vgas pressure acting downwardly on the lower arcing contact drives or impels this lower contact in a downward `direction so as to with a veryrapid motion which is independent of the slower motion of the movable main contact L In consequence thereof thearc is quickly extinguished within the arc extinguishing chamber 9|, such action being aided and abetted by the throttling and gas directing functions-of the liner rings 94, as previously described.

With regard `to the removability of the interrupter unit |50, attention is` directed to the fact that this unit can be completely removedv from the switch assembly .when the switch is either in its open position or in its closed position. It will be obvious that in the open positionne circuit relations are disturbed.` and hence theregis no p problem oi extinguishing any arc. When: the switch `is inits closed position, the arcing contacts are in shunt relation `to the main contacts, with the latter carrying the major portion oi the load, and when theinterrupter unit is re moved from the switch assembly there is no breaking of the circuit because the continuity of the circuit is maintained through the main contacts il and 14. Hence, there is no appreciable arcing between any of the parts when the inter- Y ruptingunit |50 is removed at this time. Any

repairs or replacements can be made in the in terrupter unit, and the unit then restored to its normal operative position in the switch assembly. without disturbing the relation between the` main contacts 68 and 1l. Figures 9 to 12, inclusive, illustratev a relatively simpliiled embodiment having several points of similarity to the construction shown in Figures "l and 8. Many of the reference numerals employed inthe preceding iigures have also been employed to designate similar parts in these later iigures, with the suillx d added to the numeral. The stationary main contact 14d has its upper portion externally threaded for receiving the upl per and` lower nuts I 55d and I 51d which clamp this main contact stationarily in the top of the insulator Md. An upper terminal lug or ring 16d screws down over the threaded'upper end of thecontact sleeve 14d for establishing connection with a transformer terminal or other circuit connection.` As an alternative arrangement, the transformer or other outlet terminal might be clamped between the two threaded members 16d and llld. u 4

The movable main contact 68d is secured by screws `Illdto a retaining ring 2in which is clamped to the internal flange 2li of the insulatcr l1 bya nut 2|2. The lowerend of the mov- Illd tends to thrust this rod upwardly until the v stop collar Ind at th' lower end of the rod strikes the under side oi the guide block |94d.

The cap |92d at the upper end of the follow-up` rod is adapted to bear against the lower end of the relatively movable arcing rod 89d.` An insulating sleeve ild surrounds `the lower portion of the arcing rod 89d, extending upwardly from the end cap |81d to the under side of the collar lud, this sleeve possibly serving as a shoulder for holding the collar l84d in its correct position on the arcing rod. The lighter upper spring |8211 is confined betweenthe movable collar |84d v and a stationary upper collar |83d which abuts the bottom liner ring 94 of the arc extinguishing chamber 9|. The liner rings 94 are held within an insulating sleeve |62d which has its lower end anchored against an abutment ring` IBId that screws up an internaly thread 2li formed in the` lower end of themain stationary contact 14d.`

'I'he upper arcing contact 88d is mountedl within the upper end of the insulating sleeve" |6211, which upper end projects from the upper end of the stationary upper contact sleeve 14d. The fit of this arcing contact 88d in thesleeve |6211 may be slightly loose, it desired, toallcw Isome of the gas to vent from the upper end of the arc extinguishing chamber. Atransverse pin 2l! passes through the insulating sleeve IlZd` and upper arcing contact 88d and secures the two together. The opposite ends of this pin project beyond the insulating sleeve :for quick detach-` able cooperation with L shaped bayonet slots 2|6 (Fig. 11) formed at diametrically opposite sides 4 of the metal sleeve 14d'. Formed integral with the upper end of the` upper arcing contact 88d is a shouldered head 2|1 which abuts against the upper end oi the insulating sleeve |62d. A trans.- verse slot 218 extends across the top of the head 2|l for establishing operative connection with `a removing tool, such as shown in Figure 12. A

compression spring 2|! abutting against the un-` der side of the head 2| 'I is adapted to be coinpressed against the upper end of `the metallic sleeve 14d when the removable interrupter unit Iiiid is in place in the assembly, this spring keeping the ends of the pin 2| 5 pressed ilrmly upwardly against the upper sides of the lateral ends of the bayonet slots 2| B. 'I'he electrical connec-V adapted to engage down in the slot 2|8 in the head 2|1.

The operation of thisembodiment will be apparent from the description Jof the preceding em bodiment. Figure 9 illustrates `the switch in its closed position and Figure 10 illustrates the switch in its open position. l

When it is desired to remove the removable in- .terrupterunit Ind from the Vswitch assembly, the

removing tool 22| is engaged over the interrupter head 2H, -wlth the pin 225l engaging in the slot` 2|8. Rotation of the removing `tool now releases the ends of the pin 2|! from the lateral ends of the bayonet slots` 2|8, so that the entire interrupter unit IBld can be pulled directly out o! the s witch assembly through the friction grip of the resilient socket ilngers nl'. The interrupter unit can be removed and replaced either while the switch is in the closed circuit position (Figure 9) or in the open circuit position (Figure 10) without interfering in any way with the main switch contacts or drawing any arc.

My invention also contemplates using the interrupter unitalone as a Vcomplete switching unit without embodying it in an isolator switch or substantially at the lower edge of the internal nut or ring Ild, so that there would be no lower contacting portion of this sleeve. Hence, there would be no main contacts but the entire switching operation would be performed solely by the arcing contacts 88d and lid.

My invention also contemplates a construction in which the upper arcing contact would be gas impelled, like the arcing contact in Figures 3, 4, and 5, and the lowering arcing contact would also be gas impelled,like the ,arcing contact 89a or 89d of Figures 'IV and 8 or 9 and 10. In such an arrangement, the simultaneous gas impelled movement of the two arcing contacts in opposite directions wouldincrease still further the rate of separation of the two arcing contacts. Such arcing contacts mightbe arranged to have direct contact with eachother in their closed circuit positions, or they might be arranged to have contact with opposite endseof 'an intermediate contact constructed in the form of a hollow metallic ring anchored in the arc extinguishing chamber 9i in place of one oi the `insulating lining rings 94. The two arcing contacts would then be gas impelled in opposite .-directions away from this intermediate contact ring, whereby `two arcs would be drawn in series, one from each of the two arcing contacts to the intermediate contact.

While I have illustrated and described what I regard to be the preferred embodiments of my invention, nevertheless it will be understood that such-are merely exemplary and that numerous of relative separation, and an air-break type of 14 an air-break type of arc extinguishing chamber through which said second contact is adapted to travel in separating from` said first contact, said chamber comprising aseries of lining rings of fiber or like insulating material, said lining rings being formed with tapering throats to direct the gaseous products of the arc in a directtion toward saidiirst contact, and recessed areas formed in those ends of -said lining rings corresponding to the constricted throat ends thereof, said recessed areas increasing the length of the creepage .path

through said chamber.

3. In circuit interrupting apparatus, the combination of a pair of cooperating contacts capable of relative separation, and an air-break type of chamber for extinguishing the arc drawn between said contacts in such relativel separation. said chamber comprising a series of rings of insulating material, and shielding formations on said rings for protecting -the creepage lpath through the chamber from the effect of the arc drawn between said contacts.

4. In a switch of the class described, the cornbination of a pair of cooperating main contacts capable of relative movement into and out of engagement with each other, a pairof cooperating arcing contacts connected with said main contacts and also movable into and out-0f engagement with each other, an arc extinguishing chamber sur. rounding said 4arcing contacts `and. isolating the latter from said main contacts. a series o1' lining rings of insulating material in said chamber through which at least one of said arcing contacts is compelled to travel in the separating motion betweensaid arcing contacta-said lining rings being formed with tapering throats to direct the gaseous products'of thexarc diagonally inwardly into the path of the arc at an oblique angle relatively to the direction of travel of said latter contact, said lining rings having their ends substantially in contact with each other and cooperating wlthsaid arcing contacts lto form a constricted `chamber area for causing the gases ofl the arc to rise to relatively high pressures in said chamber area, means operative during the switch opening operation for causing said arcing contacts to re.-

main in engagement until after said main conl sociated with said main contacts, a removable inchamber -for extinguishing the arc drawn between said contacts in suchrelative separation, said chamber comprlsinga series of lining` rings of insulating material through which at least one of said contacts is adapted to travel, said lining rings being formed with tapering throats to direct the gaseous products of the arc in a predeterterrupter unit mounted for 4rotative releasing movement within said socket, said interrupter s unit comprising a pair of cooperatinglarcing contacts electrically connected with said main contacts and also movable into and out of engagement with each other, means operative during the switch opening operation lor causing said arcing contacts to remain in engagement until after said main contacts have separated and `for thereafter causing said arcing contacts to separate so as to draw the arc therebetween, bayonet slot holding means for holding said interrupter unit in said socket, and releasing means operative to axially rotate said interrupter unit and thereby release said bayonet slot holding means and to then remove said interrupter unit from said socket.

to direct the gaseous products of the arc diagonal- 'ly inwardly into the path or the arc.`

7. In apparatus oi the class described. the combination o! a pair of cooperating contacts capable of relative separation, and an air-break type oi arc extinguishing chamber through which at least oneiof. said contactsis adapted to travel forextinguishing thearc drawn between said contacts in such relativerv separation, said chamber comprising a pluralityot throats directing the gaseous productsoi'the arc diagonally inwardly into the path of the arc atl-an oblique angle to the line of travel of said contact.

8, In apparatus of the class described, the combination of a pair of cooperating contacts capa-ble of relative separation, and an air-break type of arc extinguishing chamber-through which at least one ofsaid contacts is adapted to travel `for extinguishing the arc drawn between said contacts in such relative separation, said chamber comprising an aligned series oi tapered throats directing air in the gaseous products of the arc diagoand having open inner ends diagonally inclined to direct air and the gaseous products of the arc diagonally inwardly into the path ofthe arc at an oblique angle to the line of travel of said contact.

i 10.` In apparatus of the class described, the combination of a pair of cooperating contacts capable of relative' separation, and an air-break type of arcextinguishing chamberthrough which at least one of said contacts is adapted to travel for extinguishing the 'arc drawn between said contacts in such relative separation, said chamber comprising a series or removable rings oi.` insulating material formed with aligned tapering 'throats having closed outer ends and having open inner ends which direct the air and gaseous products of the arc diagonally .inwardly .into the path of the arcat an oblique angle to the line of travel -of said contact, said tapering throats with their closed outer ends cooperating with said contacts to deilne a constricted chamber area for causing the gaseous products of the arc to rise to relative-` ly high pressures. e

11. In` apparatus of the class described, the

combination of ailrst contact, a second contact combination ofV a pair fof cooperating contacts capable oi' relative separation, and an air-break type of arc extinguishing chamber through which at least one of said contacts is adapted to travel for extinguishing the arc drawn between said contacts in such relative separation, said chamber comprising a series of throats having closed outer ends and having open inner ends diagonally `inclined to direct the gaseous products of the arc diagonally inwardly into the path of the arc at an oblique angle to the line of travel of said movable contact, spring means normally tending to move said movable contact away froml other contact, and control means for holding said movable contact in engagement with said other contact in opposition to the action of said spring` means. 1

13. In apparatus of the class describedthe combination of` a nrst contact, a second contact movable into and out `of engagement with said rst contact along a rectilinear path o! travel, an air-break type of are extinguishing chamber through which said movable contactv is adapted to travel for extinguishing the arc drawn between said contacts in their relative separation, said chamber comprising a. series of tapered throats directing. the gaseous products of the arc diagonally inwardly into the path of the arc at an oblique angle to therectilinear line of travel of said movable contact, the outer ends` of said throats being closed and` the inner ends having a relatively close iit with said movable contact whereby to deine a constricted chamber area for i causing the gases of the arc torise to relatively high pressures, a helical spring mounted concentrically of `said movable contact and normally tending to move said movable contact away from said rst contact, and control means for holding said movable contact in engagement with said first contact inopposition to the action of said helical spring. C

`14. In` apparatus of f the class described, `the combination of pair of cooperating contacts` capable of relative separation, an air-break `type of arc extinguishing chamber throughwhich at least one of said contacts is adapted to travel for extinguishing the arc drawn between said contacts in such relative separation, said `chamber comprising a plurality of Vthroats directing the gaseous products o f the arc diagonally inwardly into the path of the arc at an oblique angle to the line of travel of said movable contact, the outer ends of said throats being closed and the in ner ends having a relatively close iit with said movable contacts whereby to dene a constricted chamber 4area. for causing the` gases of the arc to rise to relatively high pressures, and means enabling one of said contacts to be gas impelled in a direction away from its circuit closing position by the pressures of the gases within said chamber area.

15. In apparatus of the class described, the combination of a relatively stationary contact, a relatively movable contact movable into and out of engagement with said relativelygstationary contact along a substantially rectilinear line of travel, anch-break type of arc extinguishing chamber through which said relatively movable 'contact travels in separating from said relatively stationary contact, said `chamber comprising `a series `of aligned tapering throats directing `the gaseous products of the `arc diagonally inwardly into the path of the arc at an oblique angle to the rectilinear line of travel of said movable contact,

actuating means for moving said movable con--v tact out of engagement with said relatively stationary contact, and spring means associated with said movable contact enabling said latter contact to be gas impelled in a direction away from said relatively stationary contact by the pressures of the gases within said chamber area.

16. In apparatus of the class described, th combination of a relatively stationary contact, a relatively movable contact movable into and out of engagement with said relatively stationary contact, an air-.break type of `arc extinguishing chamber through which said relatively movable contact is adapted to travel for extinguishing the arc drawn between said contacts in theirrelative separation, said chamber comprising a series of tapered throats directing air and gaseous products of the'arcl diagonally inwardly into the path of the arc at an oblique angle pointing toward said relatively stationary contact, the outer ends of said throats being closed and the inner ends having a relatively close t with ysaid movable contacts whereby to define a constricted chamber area for causing the gases of the arc to rise to relatively high pressures.

17. In apparatus of the class described, the combination of cooperating arcing contacts capable of relative separation, an air-break type of arc extinguishing chamber .through which at least one of said contacts is adapted to travel i or extinguishing the arc drawn between said `contacts in such relative separation. said chamber comprising Vthroat means constructed and arranged to direct the gaseous products of the arc diagonally inwardly into the path of the arc, cooperating main load carrying contacts connected with said arcing contacts, andimeans for causing said arcing contacts to remain in engagement until afproducts of the arc diagonally inwardly into the path of the arc, said arcing contacts being electrically connected with said main contacts, lmeans operative during the switch opening operation for causing said arcing contacts toremain in engagement. until ai'ter said main contacts have separated and for thereafter causing said arcing contacts to separate so as to draw the arc theretacts being of substantially circular outline, a pair ter said main contacts have separated and for` thereafter causing said arcing contactsto separate so as to draw the arc therebetween in said arc extinguishing chamber.

18. In apparatus oi' the class described, the combination of a pair of cooperating arcing ,ontacts capable of relative separation, an air-break type of arc extinguishing chamber through which at least one of said `arcing contacts is adaptedv to travel for extinguishing the arc drawn between said contacts in such relative separation, said chamber comprising a plurality of throats directing the gaseous products oi' the arc diagonally inwardly into the path'of the arc at an oblique angle to the line of travel of said latter contacts, cooperating relatively separable main contacts grouped substantially concentrically of said arcing contacts and arc extinguishing cham-` ber and electrically connected with said arcing contacts to carry the main part of the line load through said apparatus, and means operative during the opening of the circuit for causing said arcing contacts to remain in engagement until after said main contacts have separated.

19. In switching apparatus of the class described, the combination of a pair of cooperating main contacts capable of relative movement into and out of engagement with each other, a readily removable interrupter unit adapted to be associated with said main contacts, said interrupter unit comprising a pair of relatively separable arcing contacts and an air-break type of arc extinguishing chamber through which at least one of said arcing contacts is adapted to travel for extinguishing the arc drawn between said arcing contacts in such relative separation, said chamber comprising throat means constructed and arranged to direct the gaseous of cooperating arcing contacts capable of relative movement int'o and out of engagement with each other, said arcing contacts also being of substantially circular outline and being aligned substantially concentrically of said main `contacts,

said arcing contacts being electrically connected 'with said main contacts, means operative during the opening of the circuit for causing said arcing contacts to remain in engagement until after said main contacts have separated, and an airvbrealr; type of arc extinguishing `chamber disposed substantially concentrically of said main contacts and of said arcing contacts and through which at least one of said arcing contacts is adapted to travel for extinguishing the arc drawn between said arcing contactsin such relative separation, said chamber comprising throat means constructed and arranged to direct the gaseous products of the arc diagonally inwardly into the path of the arc.

21. Inapparatus of `the class described, the combination of a rst contact, a second contact movable into and out of engagement with said rst contact, and an air-break type of arc extinguishing chamber throughl which said second contact is adapted to travel in separating from said first contact, said chamber comprising a series of throats directing the gaseous products oi' the arc into the path of the arc in a direction counter to the direction of travel of said second contact.

22. In switching apparatus of\\the class described'the combination of a pai1\of cooperating main contacts capable of relative movement into and out of engagement with each other, a readily removable interrupter unit adapted to be associated with said main contacts, said interrupter unit comprising a pair of relatively separable arcing contacts and an air-break type of arc extinguishing chamber through which at i \arcing contacts to remain in engagement until point*l without opening said main contacts nor disconnecting them from the line, said latching -rled by said removableinterrupter unit and adapted to engage a relatively stationary latching shoulder on said `switching apparatus, and combined guiding4 and retaining .means carried by said removable interrupter unit operable to guide said removing tool into cooperative releas-` ing engagement with said pivoted `latch and to retain said removable interrupter unit on said removing tool in the operation ot'removingsaid unit from the switching apparatus after release of said pivotedlatch. n

23. In switching apparatus of the class described, the combinationof a pair of cocperat` ing main contacts capable of relative movement into and out of engagement with'each other, a readily removable interrupter unit adapted to be associated with said main contacts, said interrupter unit comprising a pair of relatively separable arclng` contactsand an air-break type of arc `extinguishing chamber through which at least one of said arcing, contacts is adapted to travel for extinguishing the arc drawnbetween said arcing contacts in suchrelative separation. said arcing contacts being electrically connected l with said main contacts, means operative during after said `main contacts have separated and iorythereafter causing saidt'arcing contacts to separate so as to draw the arc therebetweemand readily releasable latching means normally holdingsaid interrupter unit in saidlswitching apparatus but capable of being released by an insulated removing toolfrom a relatively remote point without opening said main contacts nor disconnecting them from the line, said latching means comprising a movable latch part and a relatively stationary latch part cooperating` between said removable interrupter unit and a relatively stationary portion of said switching apparatus for normally `latching said interupter unit` in place in said switching apparatus, and means carriedby said removable interrupter unit adapted to be `engaged-by said removing toolfor releasing said movable latch part from said relatively stationary latch` part and for retaining said removable interrupter unit on said removing fin combination, conductor meansbetween which an, arc is formed on interruption of the circuit,

`and an air-break type of arc extinguishing chami ber through which said arc is drawn in such interruption ot the circuit,said chamber comprislng throat means constructed and arranged tc direct the gaseous products of the are diagonally l vinwardly into the path of the arc. n

25. An electric circuit interrupter comprising in combination, conductor` means between which an are is formed on interruption of the circuit, and an arc extinguishing and conning chamber along the past of the arc from which an arc ex' tinguishin'gmedium can be evolved dueto the heat of the `arc for extinguishing the same, said chamber comprising throat means constructed and arranged to direct said arc extinguishing medium `diagonally inwardly into the path oi` the arc.

FEDER. B. HOYE.`

REFERENCES CITED The following references are of record inthe fileof this patent:

toolin the operation of removing said unit from UNITED STATES vPATENTS Number Name' Date 890,183 Scott June 9,-1908 896,210 James Aug. 18, 1908 1,536,852 Hilliard May 5,1925 1,980,471 Burnham Nov. 13, 1934 1,981,404 Whitney etal. Nov. 20, 1934 2,060,282 Clerc Nov. 10, 1936 2,065,802 Graves, Jr. Dec. 29, 1936 2,077,338 Lingal Apr. 13, 1937 2,084,936 `Bresson June 22,1937 Y 2,155,263 Flurscheim Apr. 18,- 1939 2,163,558 MacNeill -1-' June 20, 1939 2,272,380 Ludwig et al Feb. 10, 1942 `2,275,885 Bartlett Mar. 10, 1942 2,287,039 Janssen June 23,1942

` FOREIGN PATENTS Number t Country i Date 365,298 Great Britain Jan. 21, 1932 819,662 France July 12, 1937 

